[time-nuts] HP OCXO warmup graphs

[Charles Steinmetz]

Hal wrote:

>I remember seeing comments that were roughly "it takes a month" and that
>seemed like a long time.  This was a convenient opportunity to collect some
>hard data.

And, of course, it's still a matter of interpretation.  I look at 
your plot and say, Yep, it should be mostly sorted in a 
month.  Someone else might look at it and say, Looks like 3 days to 
me.  Based on your plot, what do you say?

Also note that your oscillator was unplugged for a week or two, 
presumably after being on-power and in a stable location/environment 
for a long time.  This is pretty much the best case.  Most time-nuts 
buy oscillators of unknown provenance that have been off power for 
months to years, with (maybe) a brief power-up cycle to check them 
out by the seller, then shipped across the country or halfway around 
the world.  Many of those will take much longer to stabilize than 
yours looks like it's going to take.  (I hope you're still taking 
data -- it will be interesting to see if there are any surprise jumps 
or drifts before it settles down "for good," which happens more than 
occasionally.)

What do we mean by "unknown provenance"?  I've watched breakers 
remove oscillators from equipment and toss them ten feet into a big 
metal bin.  After sale at auction, the oscillators was poured out of 
the metal bin into a pickup bed and driven across town, where they 
were shoveled (literally, with a snow shovel) out of the truck bed 
onto a concrete floor.  One of the nicer-looking oscillators was 
photographed for an ebay ad, and when one sold a random oscillator 
was pulled from the pile and shipped to the winning bidder.  If a 
customer complained, they sent another random pull and when the first 
one was returned, it was tossed back on the pile.  And this is in the 
US -- I've heard *much* scarier stories about breakers in other countries.

Best regards,

Charles